Vulnerability · Published Jun 30, 2026 · Assigned by VulnCheck

CVE-2026-56277Flowise - Hardcoded CORS Wildcard in TTS Endpoint

Medium 6.9

In plain English

A medium-severity security flaw in Flowise from Flowise. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.9Medium

Exploit odds (30 days)0.2%top 92.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Flowise before 3.1.2 sets Access-Control-Allow-Origin to a hardcoded wildcard (*) on its text-to-speech (TTS) generation endpoint (packages/server/src/controllers/text-to-speech/index.ts), independent of the server's configured CORS policy. This bypasses the server's otherwise restrictive default CORS configuration (getCorsOptions()) and allows any webpage to make cross-origin requests that trigger TTS generation using stored credentials, enabling drive-by cross-origin credential abuse.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	flowise	3.1.2	GHSA-m837-xvxr-vqwg

Affected products (as reported)

Vendor	Product	Versions
Flowise	Flowise	0 – before 3.1.2

Weakness: CWE-346 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

GitHub Security Advisory (GHSA-m837-xvxr-vqwg) vendor-advisory
VulnCheck Advisory: Flowise - Hardcoded CORS Wildcard in TTS Endpoint third-party-advisory